Heat exchanger



1965 R. w. HUGHES 3,202,210

HEAT EXGHANGER Original Filed Aug. 11, 1959 FIG. 2.

INVENTORI ROBERT W. HUGHES ATToRNEY United States Patent 3,202,210 HEAT EXQHANGER Robert W. Hughes, Greensburg, Pa., assignor to .loy Manuiacturing Company, Pittsburgh, Pa., a corporation of Pennsylvania Continuation of abandoned application Ser. No. 833,011, Aug. 11, 1959. This application Nov. 14, 1961, Ser. No. 153,253

Claims. (Cl. 165-154) This invention relates to a heat exchanger and more particularly to a heat exchanger tube having concentric flow paths. This application is a continuation of Serial No. 833,011, filed August 11, 1959, and now abandoned.

In the past heat exchangers have been constructed which have concentric elongated flow paths in which some means have been located to provide a maximum heat transferring surface. One such means comprises a thin, flat wire which is helically wound on a side thereof to form an elongated helical springlike member (see for example FIG. 3 of Patent No. 2,680,357). While such structures have been satisfactory it has been necessary at times to provide rather long lengths to obtain the desired heat exchange.

Accordingly, one object of this invention is to provide a new and improved heat exchanger comprising an elongated column having at least one pair of joined concentric flow paths.

Another object of this invention is to provide a new and improved heat exchanger comprising a flow path having its outer boundary defined by a member having a gap therein whereby such flow path is connected to an encompassing flow path.

Another object is to provide a new and improved heat exchanger having heat conducting and heat transfer means arranged to permit a substantially greater rate of heat transfer in a direction laterally than in a direction axially therein.

A more specific object of this invention is to provide a new and improved heat exchanger having an elongated spirally wound member with the convolutions thereof axially spaced from each other to provide a pair of joined concentric flow paths.

Still another more specific object of this invention is to provide a new and improved heat exchanger having an elongated hollow spirally wound member with a spiral gap therein for providing a lateral flow path between the concentric flow paths.

These and other objects and advantages of this invention will be clearly apparent when taken in conjunction with the following drawings in which:

FIG. 1 is a partial side elevational and partial cross sectional view of a heat exchanger constructed in accordance with the principles of this invention.

FIG. 2 is a partial side elevational and partial cross sectional view of another heat exchanger constructed in accordance with the principles of this invention.

Referring to FIG. 1 it will be noted that a heat exchanger constructed in accordance with the principles of this invention comprises an elongated tube 2 having an elongated spiral springlike member 4 tightly wound over and suitably secured to the outer surface thereof. The member 4 is formed by helically wrapping on edge a thin flat narrow strip of good heat conducting metal to form an elongated spiral finlike member as shown in the Collins Patent No. 2,494,286 which finlike member is wrapped around the outer surface of the tube 2 so that each convolution engages a convolution on each side thereof. In order to accomplish the purposes of this invention an elongated fiat ribbon 6 is helically wound over the outer surface of the member 4 with its inner surface tightly engaging the outer edges of the convolutions of smarts Patented Aug. 24, 1965 the member 4 without causing crushing thereof. It will be noted however that each convolution of the ribbon 6 is axially spaced from its adjacent convolution to form a gap -8 therein extending he'lically along th outer surface of the member 4.

An elongated spiral fin'like member 10, similar to the member 4 but having a larger winding diameter, is tightly wound about the outer surface of the ribbon 6. Ribbon 6 forms a wall between the annular space filled by members 4 and the annular space filled by member 10. It can be readily seen that the wall formed by ribbon 6 divides the passageway between tube 2 and tube 12 into two portions so as to provide one flow path between tube 2 and ribbon 6 and another flow path between ribbon 6 and tube 12. A tube 12 is next inserted over the entire assembly previously described so as to enclose the tube 2, members 4 and 10 and ribbon 6. Thereafter, a spiral finlike member 14 and a tube 16 are alternately located radially outwardly of the tube 16. If desired, additional members 14 and tubes '16 may be provided asshown in construction lines in FIG. 1. With such construction the spiral members 4, 10 and 14 fill the annular spaces between the tube 2 and the ribbon 6, the ribbon 6 and the tube 12 and the tubes 12 and 16, respectively, and all of such tubes, spiral members and ribbon encompass the tube 2. Although tubes 12 and 16, spiral members 4, 1t and 14 and ribbon 6 are shown as being concentric with the tube 2 it should be realized that an eccentric arrangement of such tubes, spiral members and ribbons with respect to tube 2 may be made if so desired.

For the purpose of this invention th tubes 2, 12 and.

16, spiral members 4, :10 and 14 and the ribbon 6 are formed from any suitable good heat conducting material such as copper to readily permit their formation to close tolerance and securement together. Such tubes, spiral members and ribbon may be secured in any suitable manner, however, it will readily be appreciated that the teaching of Patent No. 2,494,286 is particularly applicable to the described structure. Patent No. 2,494,286 does not disclose the Winding of a ribbon such as ribbon 6, however, such winding can readily be accomplished in various well known manners and particularly so in view of the teaching of such patent.

From this description it will be seen that the flow paths having the spiral members 4 and 10 therein are laterally connected by means of the helical gap 8. Since the gap 8 extends the entire axial length of the spiral members 4 and 10, the spiral members 4 and 10 are thermally joined or united throughout their length so as to eliminate any thermal eddies or preferential thermal flow through either one which can occur when the members 4 and 1% are separated by a tubular member. Since the spiral members 4 and 10 constitute, from a thermal standpoint, a single passageway they are necessarily wound with their convolutions progressing in one axial direction which, as shown, is from left to right. The ribbon 6 may be Wound with its spaced helical convolutions progrossing in either axial direction, but preferably, and as shown, progresses in an axial direction opposite that of the spiral members 4 and 1d. The spiral member .14 may be wound in either axial direction depending on Whether a counter flow or parallel flow heat exchanger is desired. It will be obvious that if desired the tube 2 may,v also be employed to conduct a fluid through the heat exchanger. Although not shown it will be realized that the tubes 2, 12 and 16 are suitably secured to suitable header constructions as are Well known in the art to obtain the desired fluid flow therethough.

FIG. 2 illustrates another heat exchanger constructed in accordance with the principles of this invention. Such structure is similar to the previously described structure and accordingly like parts have been identified by the same reference numeral. in this embodiment a ribbon shaped tube 6 having an elongated hollow cross section is wound in the same manner as the ribbon 6 previously described so that a fluid may flow therethrough between the spiral members 4 and lit. The tube 6' may also be suitably secured to a suitable header construction.

Although in both embodiments only two parallel flow paths are shown connected by a helical member it will be obvious that any plurality of adjacent channels may be so separated as required by the thermodynamics of a particular application. Also although a heat exchanger assembly which is packed with spiral members 4 and iii has been shown such packing can if desired be eliminated or other types of packing employed, as such packing is for the purpose of obtaining the maximum surface area in a flow path. Further, a thin perforated or slotted tube made of good conducting material may be substituted for ribbon 6. Having described a preferred embodiment of this invention in accordance with the patent statutes it is to be realized that modifications thereof may be 'made without departing from the broad spirit and scope of the invention. Accordingly it is respectfully requested that this invention be interpreted as broadly as possible and be limited only by the prior art.

What I claim as new and desire to secure by Letters Patent is:

1. In a heat exchanger having a pair of elongated tubular members one of which encompasses the other and is laterally spaced therefrom and at least one of which is of a heat transferring material and which tubular members define a fluid flow path therebetween which path is divided into two parallel portions by means of an elongated heat transferring member extending axially of and intermediate said tubular members with each of said parallel portions having heat transfer means closely received therein to obtain a substantially greater rate of heat transfer in a direction laterally of said tubular members than in a direction axially thereof, the improvement comprising, having openings in said heat transferring member such that said heat transferring member has no rectilinear thermal fiow path longitudinally between the end portions thereof and to permit iluid flow laterally be-' tween said parallel portions.

2. A heat exchanger as defined in claim 1 in which said heat transferring member is hollow to define a fluid fiow passageway therethrough.

3. A heat exchanger as defined in claim 1 in which said heat transferring member comprises a helically formed hollow member to form a helically extending gap and to define a fluid flow passageway therethrough.

4-. In a heat exchanger having a pair of elongated tubular members one of which encompasses the other and is laterally spaced therefrom and at least one of which is of a heat transferring material and which tubular members define a fluid flow path therebetween which path is divided into two parallel portions by means of an elongated heat transferring member extending axially of and intermediate said tubular members with each of said parallel portions having heat transfer means closely received therein to obtain a substantially greater rate of heat transfer in a direction laterally of said tubular members than in a direction axially thereof, the improvement comprising, said heat transferring member being a helically wound ribbon forming a helically extending gap such that said heat transferring member has no rectilinear thermal flow path longitudinally between the end portions thereof and to permit fiuid flow laterally between said parallel portions.

5. A heat exchanger as defined in claim 4 in which said heat transfer means are helically extending members opposite in hand to the helix of said ribbon.

References Cited by the Examiner UNITED STATES PATENTS 1,716,333 6/29 Vuilleumier 257-262.1O

2,282,627 5/42 Weiss -168 X 2,680,357 6/ 54 Collins 6238 CHARLES SUKALO, Primary Examiner. 

1. IN A HEAT EXCHANGER HAVING A PAIR OF ELONGATED TUBULAR MEMBERS ONE OF WHICH ENCOMPASSES THE OTHER AND IS LATERALLY SPACED THEREFROM AND AT LEAST ONE OF WHICH IS OF A HEAT TRANSFERRING MATERIAL AND WHICH TUBULAR MEMBERS DEFINE A FLUID FLOW PATH THEREBETWEEN WHICH PATH IS DIVIDED INTO TWO PARALLEL PORTIONS BY MEANS OF AN ELONGATED HEAT TRANSFERRING MEMBER EXTENDING AXIALLY OF AND INTERMEDIATE SAID TUBULAR MEMBERS WITH EACH OF SAID PARALLEL PORTIONS HAVING HEAT TRANSFER MEANS CLOSELY RECEIVED THEREIN TO OBTAIN A SUBSTANTIALLY GREATER RATE TO HEAT TRANSFER IN A DIRECTION LATERALLY OF SAID TUBULAR MEMBERS THAN IN A DIRECTION AXIALLY THEREOF, THE IMPROVEMENT COMPRISING, HAVING OPENINGS IN SAID HEAT TRANSFERRING MEMBER SUCH THAT SAID HEAT TRANSFERRING MEMBER HAS NO RECTILINEAR THERMAL FLOW PATH LONGITUDINALLY BETWEEN THE END PORTIONS THEREOF AND TO PERMIT FLUID FLOW LATERALLY BETWEEN SAID PARALLEL PORTIONS. 